Exposure to air pollution as an environmental determinant of how Sjögren's disease is expressed at diagnosis

OBJECTIVES

To analyse how the potential exposure to air pollutants can influence the key components at the time of diagnosis of Sjögren's phenotype (epidemiological profile, sicca symptoms, and systemic disease).

METHODS

For the present study, the following variables were selected for harmonization and refinement: age, sex, country, fulfilment of 2002/2016 criteria items, dry eyes, dry mouth, and overall ESSDAI score. Air pollution indexes per country were defined according to the OECD (1990-2021), including emission data of nitrogen and sulphur oxides (NO/SO), particulate matter (PM2.5 and 1.0), carbon monoxide (CO) and volatile organic compounds (VOC) calculated per unit of GDP, Kg per 1000 USD.

RESULTS

The results of the chi-square tests of independence for each air pollutant with the frequency of dry eyes at diagnosis showed that, except for one, all variables exhibited p-values <0.0001. The most pronounced disparities emerged in the dry eye prevalence among individuals inhabiting countries with the highest NO/SO exposure, a surge of 4.61 percentage points compared to other countries, followed by CO (3.59 points), non-methane (3.32 points), PM2.5 (3.30 points), and PM1.0 (1.60 points) exposures. Concerning dry mouth, individuals residing in countries with worse NO/SO exposures exhibited a heightened frequency of dry mouth by 2.05 percentage points (p<0.0001), followed by non-methane exposure (1.21 percentage points increase, p=0.007). Individuals inhabiting countries with the worst NO/SO, CO, and PM2.5 pollution levels had a higher mean global ESSDAI score than those in lower-risk nations (all p-values <0.0001). When systemic disease was stratified according to DAS into low, moderate, and high systemic activity levels, a heightened proportion of individuals manifesting moderate/severe systemic activity was observed in countries with worse exposures to NO/SO, CO, and PM2.5 pollutant levels.

CONCLUSIONS

For the first time, we suggest that pollution levels could influence how SjD appears at diagnosis in a large international cohort of patients. The most notable relationships were found between symptoms (dryness and general body symptoms) and NO/SO, CO, and PM2.5 levels.

Interferons and systemic lupus erythematosus: Pathogenesis, clinical features, and treatments in interferon-driven disease

Type I interferons (IFNs) have recently received a lot of attention with the elucidation of the pathogenesis of systemic lupus erythematosus (SLE). Type I IFNs are associated with many SLE symptoms and play a role in the pathogenesis of autoimmune diseases that may occur concurrently with SLE, such as Sjögren's syndrome, antiphospholipid syndrome, myositis, scleroderma, and interferonopathy. Type I IFNs could be the link between these diseases. However, direct measurement of type I IFN levels and the IFN gene signature is currently unavailable in clinical practice. This review discusses type I IFN signalling in SLE, investigates the role of type I IFN in the clinical manifestations and symptoms associated with SLE and other IFN-related diseases, and discusses the clinical tests that can be used to diagnose SLE and measure disease activity. In addition, the role of type I IFN-blocking therapies as potential treatments for SLE is discussed.

Lessons from Animal Models in Sjögren's Syndrome

Primary Sjögren's syndrome (pSS) is a connective tissue disease characterized by a wide spectrum of clinical features, extending from a benign glandular disease to an aggressive systemic disorder and/or lymphoma. The pathogenesis of Sjögren's syndrome (SS) is not completely understood, but it is assumed that pathogenesis of SS is multifactorial. The studies based on the animal models of SS provided significant insight in SS disease pathogenesis and management. The aim of this review is to summarize current studies on animal models with primary SS-like symptoms and discuss the impact of these studies on better understanding pathogenesis and management of Sjögren's syndrome. Databases PubMed, Web of Science, Scopus and Cochrane library were searched for summarizing studies on animal models in SS. Available data demonstrate that animal models are highly important for our understanding of SS disease.

Exploiting the role of T cells in the pathogenesis of Sjögren's syndrome for therapeutic treatment

Sjögrens syndrome (SS) is caused by autoantibodies that attack proprioceptive salivary and lacrimal gland tissues. Damage to the glands leads to dry mouth and eyes and affects multiple systems and organs. In severe cases, SS is life-threatening because it can lead to interstitial lung disease, renal insufficiency, and lymphoma. Histological examination of the labial minor salivary glands of patients with SS reveals focal lymphocyte aggregation of T and B cells. More studies have been conducted on the role of B cells in the pathogenesis of SS, whereas the role of T cells has only recently attracted the attention of researchers. This review focusses on the role of various populations of T cells in the pathogenesis of SS and the progress made in research to therapeutically targeting T cells for the treatment of patients with SS.

Qing Zao Fang (QZF) Alleviates the Inflammatory Microenvironment of the Submandibular Gland in Sjögren's Syndrome Based on the PI3K/Akt/HIF-1α/VEGF Signaling Pathway

Sjögren's syndrome (SS) which could lead to a disorder of our immune system is a chronic autoimmune disease characterized by invading exocrine glands such as salivary glands and lacrimal glands and other exocrine glands. Its common symptom is dry mouth and dry eyes, often accompanied by a large number of lymphocyte infiltrations and can involve other organs to cause complex clinical manifestations. In this study, we aimed at investigating the effect of QZF in SS, identifying the molecular mechanism in modulating autoimmune response, and determining the important roles of these factors' function as a modulator in the pathogenesis of SS. The NOD mice were utilized to establish the rats' model of Sjögren's syndrome. After 10 weeks' hydroxychloroquine and QZF in different dose interference, submandibular gland tissue was collected. The therapeutic effect of QZF on SS rats was identified, and the results suggest the comparable potential to hydroxychloroquine. In submandibular gland tissue, interleukin- (IL-) 17 was significantly lower in high-dose QZF than that in SS rats and the focal lymphocytes were highly attenuated. Moreover, we found that PI3K/Akt signals were activated and the downstream HIF-1α/VEGF signals were enhanced in SS rats whose protein expression could be inhibited by QZF treatment. In addition, QZF could modulate autophagy in submandibular gland tissue and then inhibit the inflammation response and therefore facilitate the tissue repair.

Integrative epigenomics in Sjögren´s syndrome reveals novel pathways and a strong interaction between the HLA, autoantibodies and the interferon signature

Primary Sjögren's syndrome (SS) is a systemic autoimmune disease characterized by lymphocytic infiltration and damage of exocrine salivary and lacrimal glands. The etiology of SS is complex with environmental triggers and genetic factors involved. By conducting an integrated multi-omics study, we confirmed a vast coordinated hypomethylation and overexpression effects in IFN-related genes, what is known as the IFN signature. Stratified and conditional analyses suggest a strong interaction between SS-associated HLA genetic variation and the presence of Anti-Ro/SSA autoantibodies in driving the IFN epigenetic signature and determining SS. We report a novel epigenetic signature characterized by increased DNA methylation levels in a large number of genes enriched in pathways such as collagen metabolism and extracellular matrix organization. We identified potential new genetic variants associated with SS that might mediate their risk by altering DNA methylation or gene expression patterns, as well as disease-interacting genetic variants that exhibit regulatory function only in the SS population. Our study sheds new light on the interaction between genetics, autoantibody profiles, DNA methylation and gene expression in SS, and contributes to elucidate the genetic architecture of gene regulation in an autoimmune population.

Metformin as a Treatment Strategy for Sjögren's Syndrome

Sjögren’s syndrome (SS), a chronic inflammatory disease involving the salivary and lacrimal glands, presents symptoms of sicca as well as systemic manifestations such as fatigue and musculoskeletal pain. Only a few treatments have been successful in management of SS; thus treatment of the disease is challenging. Metformin is the first-line agent for type 2 diabetes and has anti-inflammatory potential. Its immunomodulatory capacity is exerted via activation of 5’ adenosine monophosphate-activated protein kinase (AMPK). Metformin inhibits mitochondrial respiratory chain complex I which leads to change in adenosine mono-phosphate (AMP) to adenosine tri-phosphate (ATP) ratio. This results in AMPK activation and causes inhibition of mammalian target of rapamycin (mTOR). mTOR plays an important role in T cell differentiation and mTOR deficient T cells differentiate into regulatory T cells. In this manner, metformin enhances immunoregulatory response in an individual. mTOR is responsible for B cell proliferation and germinal center (GC) differentiation. Thus, reduction of B cell differentiation into antibody-producing plasma cells occurs via downregulation of mTOR. Due to the lack of suggested treatment for SS, metformin has been considered as a treatment strategy and is expected to ameliorate salivary gland function.

Cytokine profiles and clinical characteristics in primary Sjögren´s syndrome patient groups

BACKGROUND

Primary Sjögren's syndrome (pSS) is an autoimmune disease characterized by a lymphocytic infiltrate in salivary glands driving to epithelial damage. The pSS patients present heterogenic clinical and serological characteristics. This heterogenicity could be due to the cytokine microenvironment. Cytokine levels have been analyzed and reported individually, showing controversial results; for that reason, we considered essential to evaluate a cluster of cytokines and relate them with antibody levels and clinical characteristics to find pSS subgroups.

METHODS

Ninety-nine pSS patients, diagnosed by the 2016 ACR/EULAR classification criteria, and 76 control subjects (CS) were included. Cytokine quantification was performed by Multiplex assay. Principal component analysis (PCA) was realized, and the K-mean test was used to identify clusters/groups. Groups were analyzed by the Kruskal-Wallis test and the Bonferroni test.

RESULTS

Higher IFN-γ, IL-17F, IL-21, IL-23, IL-4, and IL-31 levels were observed in pSS patients in comparison with control subjects. PCA analysis showed three groups. The severe group was characterized by higher cytokine concentrations as well as an increase in clinical parameters such as antibody levels, damage index score, and others. The moderate group presented intermediate severity; meanwhile, the mild group presented the lowest severity.

CONCLUSION

Cluster analysis revealed three groups that were different in cytokine levels and clinical parameters in which the mild group was defined by lower severity, the moderate group with intermediate severity, and the severe group with higher severity. This analysis could help subclassify the primary Sjögren syndrome patients for a better understanding of the clinical phenotype that impacts the treatment approach.

Early diagnosis and treatment for Sjögren's syndrome: current challenges, redefined disease stages and future prospects

There are some challenges and unmet needs in the early diagnosis and management of Sjögren's syndrome (SjS) such as prominent glandular dysfunction at diagnosis and long diagnostic delay. Those challenges are partly attributed to the lack of a good knowledge of the early stages of SjS, which is a major obstacle to delivering appropriate care to SjS patients. Findings from both clinical and experimental studies suggest the plausibility of a redefined SjS course consisting of 4 stages, which includes initiation stage, preclinical stage, asymptomatic SjS stage and overt SjS stage. More studies focusing on the pathological processes and changes during the early stages of SjS are needed. To enable early diagnosis and treatment for SjS, more useful biomarkers of the early stages of SjS need to be identified, and individuals at high risk of SjS development need to be identified. Appropriate screening can be performed to facilitate the early diagnosis of SjS among those high-risk individuals.

Can Gut Microbiota Affect Dry Eye Syndrome?

Using metagenomics, continuing evidence has elicited how intestinal microbiota trigger distant autoimmunity. Sjögren's syndrome (SS) is an autoimmune disease that affects the ocular surface, with frequently unmet therapeutic needs requiring new interventions for dry eye management. Current studies also suggest the possible relation of autoimmune dry eye with gut microbiota. Herein, we review the current knowledge of how the gut microbiota interact with the immune system in homeostasis as well as its influence on rheumatic and ocular autoimmune diseases, and compare their characteristics with SS. Both rodent and human studies regarding gut microbiota in SS and environmental dry eye are explored, and the effects of prebiotics and probiotics on dry eye are discussed. Recent clinical studies have commonly observed a correlation between gut dysbiosis and clinical manifestations of SS, while environmental dry eye portrays characteristics in between normal and autoimmune. Moreover, a decrease in both the Firmicutes/Bacteroidetes ratio and genus Faecalibacterium have most commonly been observed in SS subjects. The presumable pathways forming the "gut dysbiosis-ocular surface-lacrimal gland axis" are introduced. This review may provide perspectives into the link between the gut microbiome and dry eye, enhance our understanding of the pathogenesis in autoimmune dry eye, and be useful in the development of future interventions.

Risk of incident autoimmune diseases in patients with thymectomy

OBJECTIVES

The data concerning the association between Tx and ADs remain unclear and are scarce. This study was undertaken to investigate whether people with Tx are more likely to develop ADs, compared to those without Tx.

METHODS

Individuals who received Tx between 2002 and 2015 were identified and matched on age and sex with individuals without Tx. We performed multivariate and stratified analysis using the Kaplan-Meier method and Cox proportional hazards models in order to estimate the association between Tx and the risk of developing ADs.

RESULTS

A total of 2550 thymectomized (Txd) patients and 24,664.941 non-Txd comparison subjects were selected from NHIRD. Tx-MG (myasthenia gravis) as compared with general population (nonTx-nonMG), adjusted hazard ratio (aHR) were higher for incident Addison disease (aHR = 10.40, 95% CI 1.01-107), autoimmune hemolytic anemia (aHR = 21.54, 95% CI 2.06-14.8), Hashmoto thyroiditis (aHR = 5.52, 95% CI 1.34-34.7), ankylosing spondylitis (aHR = 2.73, 95% CI 1.09-6.84), rheumatoid arthritis (aHR = 5.25, 95% CI 1.79-15.47), primary Sjogren syndrome (pSS) (aHR = 3.77, 95% CI 1.30-11.0), and systemic lupus erythemtoasus (aHR = 10.40). Tx-nonMG as compared with general population, aHR were higher for incident autoimmune hemolytic anemia (aHR = 25.50), Hashmoto thyroiditis (aHR = 6.75) and systemic lupus erythematosus (SLE) (aHR = 13.38). NonTx-MG as compared with general population, aHR were higher for incident Hashmoto thyroiditis (aHR = 6.57), pSS (aHR = 4.50), SLE (aHR = 17.29), and systemic vasculitis (aHR = 25.86).

INTERPRETATION

In conclusion, based on a retrospective cohort study throughout Taiwan, patients with Tx have a higher risk of new onset ADs than patients without Tx.

Expression of BAFF and BAFF receptors in primary Sjögren's syndrome patients with ectopic germinal center-like structures

B cell-activating factor (BAFF) is an essential cytokine in primary Sjögren's syndrome (pSS) physiopathology. It has been reported that pSS patients develop germinal center-like (GC-like) structures in their minor salivary glands (MSGs). BAFF, BAFF-R, TACI, and BCMA expression was analyzed in MSGs from 29 subjects (nonspecific chronic sialadenitis and focal lymphocytic sialadenitis with the presence [pSS-GC(+)] or absence [pSS-GC(-)] of GC-like structures). Twenty-four percent of patients showed ectopic GC-like structures and a high focus score [p < 0.001 vs pSS-GC(-)]. BAFF serum levels (sBAFF) were high in pSS patients (p = 0.025 vs healthy subjects). However, the pSS-GC(-) group showed higher sBAFF levels than pSS-GC(+) patients. BAFF and BAFF-R glandular expression levels were higher in pSS-GC(+) patients, without significant differences compared to pSS-GC(-) patients. Soluble levels of BAFF correlated with anti-La/SSB antibodies and disease duration. Our results showed that BAFF could contribute to focal lymphocytic infiltration. The role of BAFF-binding receptors in MSGs is proposed as a mechanism for the possible establishment of ectopic GC-like structures and disease progression in some patients. In conclusion, this study supports previous evidence that considers the active BAFF system role in the pathogenesis of pSS and the need for strong biomarkers in this disease.

Agonist-induced 4-1BB activation prevents the development of Sjӧgren's syndrome-like sialadenitis in non-obese diabetic mice

Activation of costimulatory receptor 4-1BB enhances T helper 1 (Th1) and CD8 T cell responses in protective immunity, and prevents or attenuates several autoimmune diseases by increasing Treg numbers and suppressing Th17 or Th2 effector response. We undertook this study to elucidate the impact of enforced 4-1BB activation on the development of Sjögren's syndrome (SS)-like sialadenitis in non-obese diabetic (NOD) model of this disease. An anti-4-1BB agnostic antibody was intraperitoneally injected to female NOD mice aged 7 weeks, prior to the disease onset that occurs around 10-11 weeks of age, 3 times weekly for 2 weeks, and the mice were analyzed for SS pathologies at age 11 weeks. The salivary flow rate was markedly higher in the anti-4-1BB-treated NOD mice compared to the IgG-treated controls. Anti-4-1BB treatment significantly reduced the leukocyte infiltration of the submandibular glands (SMGs) and the levels of serum antinuclear antibodies. Flow cytometric analysis showed that the percentages of CD4 T cells, Th17 cells and plasmacytoid dendritic cells among SMG leukocytes were markedly reduced by anti-4-1BB treatment, in conjunction with a reduction in SMG IL-23p19 mRNA levels and serum IL-17 concentrations. Although the proportion of Tregs and IL-10 mRNA levels in SMGs were not altered by 4-1BB activation, IL-10 mRNA levels in salivary gland-draining lymph nodes and serum IL-10 concentrations were both markedly increased. While anti-4-1BB treatment did not affect the amount of Th1 cells and IFNγ mRNA in the SMGs, it increased these measurables in salivary gland-draining lymph nodes. Hence, agonistic activation of 4-1BB impedes the development of SS-like sialadenitis and hyposalivation.

Dual function of miR-1248 links interferon induction and calcium signaling defects in Sjögren's syndrome

BACKGROUND

Sjögren's syndrome (SS) is one of the most common autoimmune disorders leading to exocrine gland dysfunction. Both immune-dependent processes - like Type I Interferon (IFN) signaling and immune-independent processes - such as calcium signaling in epithelial cells - contribute to disease pathophysiology. However, a mechanistic link between these processes has not been demonstrated.

METHODS

Primary human salivary gland cells were used to evaluate the differential expression of miRNAs with smRNA-seq in primary epithelial cells culture and digital PCR was conducted in SS human salivary glands (SG) biopsies to verify the results. With siRNA screening and pull-down assays to establish the role of miRNA in IFN activation.

FINDINGS

Activation of IFN-β by miR-1248 is through the direct association with both RIG-I and AGO2. Further functional studies establish a unique dual functional role of miR-1248 in phSG cells: i) activation of the RIG-I pathway by acting as ligand of this sensor leading to IFN production and ii) regulation of the expression of mRNAs through the canonical microRNA function. Importantly, ITPR3, a key component of calcium signaling in epithelial cells, that has previously shown to be downregulated in SS SG, was directly targeted and downregulated by miR-1248, inducing the same functional calcium signaling changes as observed in SS SGs.

INTERPRETATION

Identification of the first endogenous mammalian microRNA that binds to RIG-I inducing IFN production but also demonstrate a novel pathophysiological underlying mechanism in which miR-1248 overexpression links two major pathways associated with SS, namely activation of IFN production with modulation of calcium signaling. Together, these findings suggest a unifying hypothesis for the immune-independent and -dependent processes contributing to the pathogenesis of SS. FUND: This research was supported by the Intramural Research Program of the National Institutes of Health (NIH), National Institute of Dental and Craniofacial Research (NIDCR).

The role of Epstein-Barr virus infection in primary Sjögren's syndrome

PURPOSE OF REVIEW

The purpose of this article is to draw attention to the role of Epstein-Barr virus (EBV) virus in the pathogenesis of the primary Sjögren's syndrome. The article introduces the problem of consequences of EBV acute infection, and its reactivation, in association with the immune response modulation by the virus and with an increased risk of developing systemic autoimmune diseases and EBV-associated cancers.

RECENT FINDINGS

The knowledge about the mechanisms by which the virus may stay for years in a latent phase, unrecognized by the host response immune cells is constantly expanding. There are several mechanisms and theories about EBV influence on the autoimmune process in Sjogren's syndrome (pSS), including the similarity (molecular mimicry) between viral EBNA-2 protein and Ro-60 antigen or EBER-1 and EBER-2 viral proteins and La antigen.

SUMMARY

The influence of EBV infection on the development and course of pSS has been proven. It has also been established that both EBV and pSS result in the increased risk of tumor (especially lymphoma) development. In the light of these findings, new ways to manage EBV infections are being sought. Optimal methods for assessing EBV infection status are being devised. Research also aims at finding therapies, which target EBV through the inhibition of the autoimmune process and of viral activity. The present article is an attempt to discuss the most important phenomena and elements linking EBV infection to the primary Sjögren's syndrome.

Neuro-Sjögren: Peripheral Neuropathy With Limb Weakness in Sjögren's Syndrome

Objective: Sjögren's syndrome is a heterogeneous inflammatory disorder frequently involving peripheral nerves with a wide spectrum of sensory modalities and distribution patterns. The objective of this cross-sectional study was to determine characteristics of Sjögren's syndrome as a cause for severe neuropathy with limb weakness. Methods: One hundred and eighty four patients with polyneuropathy associated with limb weakness underwent routine diagnostics including investigations for Sjögren's syndrome. Forty-four patients with Sjögren's syndrome (ACR-EULAR classification criteria) and severe neuropathy were identified. Results: Sjögren's syndrome was found at a median age of 63 years and the gender distribution showed a balanced female-male ratio of 1:1. Anti-SSA(Ro) antibodies were detected in 48% while seronegative patients were diagnosed with Sjögren's syndrome based on sialadenitis on minor salivary gland biopsy with a focus score ≥1. The majority of patients (93%) were diagnosed with Sjögren's syndrome after neurological symptoms appeared. Limbs were symmetrically involved in 84% of patients (57% tetraparesis, 27% paraparesis). Sensory function was not affected in 11% of patients indicating that Sjögren's syndrome associated neuropathy can present as a pure motor syndrome. Electrophysiological measurements did not reveal pathognomonic findings (23% demyelinating pattern, 36% axonal pattern, 41% both demyelinating and axonal damage signs). More than half of our patients fulfilled the European Federation of Neurological Societies (EFNS) diagnostic criteria for CIDP indicating that distinction between Neuro-Sjögren and other causes of neuropathy such as CIDP is challenging. Interpretation: Our findings show that severe neuropathy with limb weakness is often associated with Sjögren's syndrome. This is of great importance in identifying and understanding the causes of immune mediated polyneuropathy.

Overexpression of Smac is associated with the development of primary Sjogren's syndrome

BACKGROUND

Primary Sjögren's syndrome (pSS) is a systemic autoimmune disease characterized by keratoconjunctivitis sicca, xerostomia, and extraglandular abnormalities. The precise etiology remains unclear. Previous studies have revealed that the apoptosis played an important role in the pSS. Herein, we investigated the expression and effect of second mitochondria-derived activator of caspase (Smac) in patients with pSS and associated the expression with clinicopathological parameters.

METHODS

Smac expression was checked in labial salivary glands of surgical specimens from cases of pSS using immunohistochemistry, reverse transcription-quantitative PCR, and Western blot. The results of immunohistochemistry were analyzed for clinicopathological parameters. In addition, the content of Smac in cytoplasm and mitochondria were examined.

RESULTS

The mRNA of Smac, the content of Smac in cytoplasm, the Smac protein in the pSS patients increased significantly compared with the healthy controls (p < 0.05). The content of Smac in mitochondria decreased significantly compared with the healthy controls (p < 0.05). The integral optical density of Smac protein levels were positively correlated with IgG (r = 0.7435, p < 0.05) and erythrocyte sedimentation rate (ESR) (r = 0.7925, p < 0.05).

CONCLUSION

Smac plays an important role in the development of pSS.

Angiogenic T cells in primary Sjögren's syndrome: a double-edged sword?

OBJECTIVES

The mechanisms underlying increased cardiovascular risk in primary Sjögren's syndrome (pSS) remain unclear. Since the recently discovered angiogenic T cells (Tang) may participate in endothelial repair by cooperating with endothelial progenitor cells (EPC), we aimed to quantify and characterise Tang in the peripheral blood and minor salivary glands (MSG) of pSS patients.

METHODS

Tang (CD3+CD31+CXCR4+) and EPC (CD34+CD133+VEGFR-2+) were quantified by flow cytometry in peripheral blood samples from 36 pSS patients and 20 healthy donors. Tang subsets were assessed on the basis of CD4, CD8 and CD28 expression. Labial MSG sections from 10 pSS patients and 12 non-pSS sicca syndrome controls were subjected to immunofluorescence staining to investigate the presence of Tang and the expression of the CXCR4-ligand stromal cell-derived factor-1 (SDF-1)/CXCL12.

RESULTS

Circulating Tang cells were expanded and directly correlated to EPC in pSS. Both Tang and EPC directly correlated with disease activity as calculated with the EULAR Sjögren's syndrome disease activity index (ESSDAI). In pSS, the majority of Tang cells were CD4-CD8- double negative (DN) and lacked CD28 revealing a senescent phenotype. A subset of CD4+, CD8+ and DN Tang cells produced interleukin-17. Immunohistology revealed the exclusive presence of periductal and perivascular infiltrating Tang cells along with increased SDF-1/CXCL12 expression in pSS MSG compared to non-pSS sicca syndrome controls.

CONCLUSIONS

In pSS, Tang cells are expanded in peripheral blood and infiltrate MSG. Tang may be novel actors in pSS-related endothelial dysfunction and glandular neo-angiogenesis and inflammation.

Type I interferon signature in Sjögren's syndrome: pathophysiological and clinical implications

Type I interferons (IFN) have long been recognised as mediators of innate immune defense mechanisms against viral threats. Robust evidence over the last 15 years revealed their significant role in the pathogenesis of systemic autoimmune diseases, including systemic lupus erythematosus (SLE) and Sjögren's syndrome (SS). Despite the progress, methods of detection, initial triggers, biological functions and clinical associations in the setting of autoimmunity remain to be fully clarified. As therapeutic options for SS are currently limited, neutralising specific targets of the type I IFN pathway seems a promising option. In this review we summarise the current evidence regarding the role of type I IFN in SS.

Oral microbial flora of patients with Sicca syndrome

Primary sicca syndrome (pSS) is a systemic autoimmune disease. However, its exact etiology and pathogenesis remain elusive. Various infectious factors have been identified to be closely associated with the occurrence and development of PSS. The present study aimed to assess the composition of the oral microbial flora of patients with pSS in China in order to provide guidance for treatment. The microbial flora of nine patients with pSS and five healthy controls from East China was evaluated in saliva samples using high‑throughput sequencing. A high microbial diversity was detected in the pSS and control groups, with bacteroidetes, firmicutes and proteobacteria constituting the largest phyla in the two groups. Compared with the control group, bacteroidetes and actinobacteria were significantly more abundant in the pSS group, whereas proteobacteria were significantly less abundant. However, no significant differences in bacterial richness and diversity were observed between the two groups. According to a Kyoto Encyclopedia of Genes and Genomes linear discriminant analysis, genes regulating cell apoptosis and the immune and digestive systems were significantly upregulated in the pSS group compared with those in the control group. In conclusion, the present study provided basic data on the flora of the oral cavity in patients with pSS from East China and may serve as a reference for the treatment of this condition.

Dysregulated Marginal Zone B Cell Compartment in a Mouse Model of Sjögren's Syndrome with Ocular Inflammation

The risk of developing lymphoma in patients with Sjögren’s syndrome (SS) is 44 times higher than in the normal population with the most common lymphomas derived from marginal zone B (MZB) cells. Current understanding of the role of MZB cells in SS is primarily based on salivary gland pathology, while their contextual association with lacrimal glands and ocular manifestations largely remains unknown. We examined this possibility using a SS mouse model (thrombospondin-1 deficient (TSP1^−/−)) with well-characterized ocular disease. We determined the frequency, localization, and cytokine profiles of MZB cells and their association with an antibody response in TSP1^−/− mice treated with a TSP-derived peptide. A significantly increased frequency of MZB cells was detected in the spleens and lacrimal glands of TSP1^−/− mice in comparison to wild-type tissues as detected by immunostaining. An altered cytokine profile of TSP1^−/− MZB cells was supportive of T helper 17 (Th17)-related pathogenesis. A significantly reduced antibody response and the splenic MZB compartment against an eye-derived antigen were noted in TSP-derived peptide-treated mice. These changes correspond with the previously reported ability of the peptide to ameliorate SS-related ocular manifestations. Collectively, our results demonstrate dysregulation of MZB cells in TSP1^−/− mice and highlight their role in the context of SS-related chronic ocular surface disease.

PBC and related extrahepatic diseases

Patients with PBC have at least 60% of probability to have an autoimmune extrahepatic condition. The pathogenesis of these conditions includes a common mechanism involving both innate and adaptive immune responses targeting cholangiocytes and different extrahepatic tissues. The recent EASL guidelines recommend the management of these conditions, although detailed practical treatments have not been indicated. Autoimmune extrahepatic conditions may include: rheumatologic, endocrine, pulmonary, gastrointestinal, dermatologic diseases. This review aims to focus the most important extrahepatic autoimmune conditions associated to PBC with practical recommendation regarding diagnostic approach and management.

Ophthalmological Aspects in Allogenic Bone Marrow Transplantation: Sjögren-Like Syndrome in Graft-Versus-Host Disease

PURPOSE

A major complication of allogenic bone marrow transplantation (BMT) is graft-versus-host disease (GVHD), characterized principally by involvement of the eyes, producing a Sjögren-like syndrome (SLS). This study assessed the predictive role of the eye involvement in the onset of GVHD.

METHODS

Thirty-five patients transplanted for hematological malignancies were routinely examined for ocular manifestation of dry eye. Examination includes the Schirmer I test, break-up time, Lissamine Green staining, fluorescein test, lactoferrin test and impression cytology. A threshold was established for quantitative analysis of SLS.

RESULTS

Fifteen of 35 patients (40%) developed SLS during long-term follow-up. Ten of these (77%) developed acute or chronic GVHD.

CONCLUSIONS

The possible etiology of SLS includes three factors: total body irradiation, ocular toxicity of chemotherapy and GVHD. A correlation was found between poor-prognosis GVHD and the occurrence of SLS.

Potential Role of Free Fatty Acids in the Pathogenesis of Periodontitis and Primary Sjögren's Syndrome

Clinical studies have shown that metabolic disorders such as type 2 diabetes and dyslipidemia are associated with increased risk of oral-related diseases, such as periodontitis and Sjögren’s syndrome. Although changes in the immune system are critical in both of these metabolic disorders and oral-related diseases, the mechanism underlying the interaction between these diseases remains largely unknown. Obesity and type 2 diabetes are known to be associated with higher concentrations of free fatty acids in blood. Among free fatty acids, saturated fatty acids such as palmitic acid have been demonstrated to induce inflammatory responses mainly via the innate immune systems, and to be involved in the pathogenesis of type 2 diabetes in tissues such as adipose tissue, liver, pancreas, and skeletal muscle. Here, we highlight recent advances in evidence for the potential involvement of palmitic acid in the pathogenesis of periodontitis and Sjögren’s syndrome, and discuss the possibility that improvement of the lipid profile could be a new strategy for the treatment of these diseases.